Non-Markovianity in Discrete-Time Open Quantum Random Walk on Arbitrary Graphs

TL;DR

This paper introduces a versatile model for discrete-time open quantum walks on arbitrary graphs, analyzing the effects of non-Markovian noise channels on quantum coherence, fidelity, and probability distributions across various graph structures.

Contribution

It extends quantum walk models to arbitrary graphs and studies the influence of non-Markovian noise, providing insights into quantum dynamics beyond regular graph structures.

Findings

Noise impacts quantum coherence and fidelity over time

Probability distributions vary with different noise channels

Non-Markovian effects influence walker localization and spread

Abstract

In this work, we present a new model of the Discrete-Time Open Quantum Walk (DTOQW) applicable to an arbitrary graph, thereby going beyond the case of quantum walks on regular graphs. We study the impact of noise in the dynamics of quantum walk by applying Kraus operators of different dimensions which are constructed using the Weyl operators. The DTOQW employs these Kraus operators as its coin operators. The walker dynamics are studied under the impact of non-Markovian amplitude damping, dephasing and depolarizing noise channels. We also implement the walk on various graphs, including path graphs, cycle graphs, star graphs, complete graphs, complete bipartite graphs, etc. We gauge the dynamics by computing coherence and fidelity at different time steps, taking into account the influence of noise. Furthermore, we compute the probability distribution at different time steps for the above noises, which represents the availability of the quantum walker at different vertices of the graph.